Final answer:
The correct statement is that set A is a subset of set B.
Step-by-step explanation:
The given sets are A = (1, 2, 3) and B = (3, 2, 1). To determine which of the statements is true, we need to evaluate each option.
a) (4 in A cap B): The intersection of A and B is the set of elements that are common to both sets. In this case, A cap B = {1, 2, 3}, and 4 is not in this set, so option a is false.
b) (A subseteq B): A is a subset of B if all elements of A are also in B. In this case, all elements of A are also in B, so option b is true.
c) (A is an infinite set): A is a finite set as it has only 3 elements, so option c is false.
d) None of the above: Option d is false as option b is true.
Therefore, the correct answer is b) (A subseteq B).